To be able to introduce day light into a building has in all times been of great interest. The human being has in all times, apart from the modern era with electric light, been dependent on the daylight and has biologically evolved under this constraint. The turning of the sun during the day, from east to west, has a significant effect on peoples perception of passed time, when to have different types of meals, when to sleep and when to get up, just to mention a few.
When designing buildings the introduction of daylight, in later times particularly through glass windows, is a major design consideration. At the same time, as land prices raise in popular areas, it is of economical interest to build bigger buildings. These two requirements are at times colliding. Residential blocks are most often not wider than 9-10 meters. However, the wider buildings lack significant daylight comfort. They tend to be somewhat like darker caves. A daylight source using a daylight collector makes it possible to construct buildings with higher utilization factor.
U.S. Pat. No. 5,022,736 “Solar ray device for illumination” discloses a device comprising a solar ray collecting device having multiple optical lenses, and an illuminator connected through a plurality of light guiding cables. The device further comprises a sensor for detecting the direction of the sun's rays and for treating a control signal causing the optical lenses to be directed toward the sun.
U.S. Pat. No. 4,297,000 “Solar lighting system” disclose a solar collector device for directing solar light onto a bundle of optical fibres. The device comprises a tracking system to direct to collector device towards the sun.
JP 591,602,14 “Solar light tracking device” disclose a solar tracking device for tracking to sun using a spring of a shape memory alloy.
U.S. Pat. No. 4,050,789 “Tracking lens system for solar collectors and skylights” disclose an arrangement for collecting solar light using three layers of lenses, a first condensing lens, a second diverging lens and a third condensing lens. More over the second lens need to be positioned not only horizontally between the two condensing lenses but also vertically to focus the beam correctly. These limitations require that sophisticated and expensive mechanism for moving the middle lens. It would be beneficial if fewer lenses could be used and if a movement in only two dimensions could be achieved.
U.S. Pat. No. 4,867,514 “Systems for deviating and (optionally) converging radiation” disclose a method for collecting solar light comprising first lens and second lenses. The second lens need to be movable in direction to and from said first lens to increase or decrease the distance from the first lens as well as parallel to the first lens to collect the sun light. It would be beneficial if a movement in the direction to and from the first lens could be avoided to achieve a simpler and more cost effective solar collecting device.